1. Field of the Invention
The present invention relates to a display panel using organic electroluminescence elements and a display device in which the display panel is included.
2. Description of the Related Background Art
A display device used for a movable terminal such as a cellular phone requires a thin display panel. Although a liquid crystal display panel is usually used for the conventional thin display panel, since a display panel formed by a plurality of organic electroluminescence elements (organic EL elements) in a matrix shape is not only thin but also light, it is regarded useful as a display for the movable terminal.
In the conventional display panel of a matrix shape using the organic electroluminescence elements, a lot of organic electroluminescence elements are generally provided on a transparent substrate such as a glass and a plastic film, and in order to protect these elements from the surrounding environment such as humidity and dust, these elements are insulated on a transparent substrate by an insulation seal film such as silicon dioxide film. Therefore, in order to connect an organic EL element to a driving circuit, it is necessary to draw the electrodes directly from the organic EL element on a panel and extend this to a driving circuit outside of the display panel through the outer peripheral portion of the insulation seal film.
In the conventional display panel, adopted is the structure of forming a connection pattern by drawing a connecting electrode from the insulation seal film once and electrically connecting with the external connection pattern for power supply through an anisotropy conductive film such as Anisolm.
In this structure, however, since thermo-compression processing in forming an electric insulation by an anisotropy conductive film is required, it is defective in that the manufacturing process of display panels becomes complicated. Further, peeling of the anisotropy conductive film easily occurs in this structure, and when the anisotropy conductive film is once peeled off, it is difficult to adhere it there again.
Further, since draw of electrodes is performed from an organic EL element in the peripheral portion of a display panel, each connection of electrodes becomes difficult in the central portion on a luminescent surface. Therefore, when the electrodes are drawn from all the organic EL elements forming a display panel, a dead space occurs in the peripheral portion of the display panel, which makes the whole area of the display panel enlarge. Further, the drawing portions of the electrodes are more fragile than the other sealing portion from the viewpoint of water intrusion, which causes deterioration of the internal elements.